((Sorry about that. Fixed.))
((I'm assuming that, since Amul isn't here, that Viscaria will be out in the regio working and planning and being generally unavailable. And since she doesn't have a deputy, then Fiona will go to Korvin as the Princeps. And since he's the one who actually needs the Vis for the ritual and his fee, it's his call as to where it comes from. As long as Fiona's assured that she's done her part.))
((The arithmetics can't get much simpler than that... 
))
So if we go with six large towers at the corners of the wall and then two here and here (points to the west gate) , we would need roughly 30 of your smaller towers around the outer ring. We can fit 28 with two towers to a plot. We can save the others to place if we need them. If we provide the vis for all the rituals, what would be the cost of your time?
"Considering the time and exhaustion that comes with casting rituals, hmmm, let me think..."
((Conjuring the Mystic Tower is level 35, so 1.75 hours to cast. Conjuring the Limes Tower is level 20, so "only" one hour. The real limiting factor is long-term Fatigue Levels. I'd say about 12 days, casting up to 3 rituals per day, is reasonable. But there's a better way...))
"So we are speaking of thirty-four castings, yes? Hmmm, I could do that over a period of time during my presence here when I come back to investigate the regio entrances. Taking an hour or two each day to raise a tower would not limit my activities too much, so this could be combined."
"My fee for casting the spells would be one pawn per Limes Tower, and two pawns per Mystic Tower. So this would total up to about four rooks, half of which in that Rego Terram attuned vis you mentioned."
((Korvin can probably recognize this as an opening bid for bargaining. Int+Bargain of 6 to recognize it as such.))
1d10=4 + Bargain 2 + int 3
Half in the aligned vis! You ask too much. I will meet you price but 1 rook of the ReTe vis and you must supply Mons electi a lab text of the Limes Tower.
1d10=1 + 1d10=7 14 + guile 1 plus com 2 = 18
Korvin seems sincere in his response.
Petronius mulls over your counter-offer, before shaking his head, "I could sell you the lab text, of course, but that would have to be paid seperatedly. But considering this is for Tribunal purposes, I may be willing to decrease my fee a little, even if it is not my Tribunal. Say, a five pawns rebate. Mind you, the vis would have to be in Arts that are useful to me and my research. So eighteen pawns of aligned vis, with the rest mostly Vim or something equivalent. I have little use for Mentem or Imaginem, for example. I can understand that you would need most of your Terram and Creo to raise the towers themselves."
"In fact, as I've mentioned, I exchange some of the vis required for the rituals at favourable terms for aligned vis. My covenant has some stores of the appropriate Arts."
18 pawns is still high considering I will have to exchange some of our vis for Terram and Creo as it is. No. i will give you 12 pawns of the ReTe vis and 20 of other vis and 8 pawns of Rego. I still will want that lab text.
"Let us split it midway," Petronius counters as the magi walk back towards the covenant. I will throw in a copy of the lab text as a gesture of goodwill. But it will be fifteen pawns of aligned vis and twenty-five of other Arts that are acceptable to me. As I said, most Forms are of limited use in my research, so I will not accept any large number of pawns in Arts that I have no use for."
Korvin chuckles. I enjoy bargaining with you. So much so I will tell you a secret. We really have quite a bit of the ReTe vis. I will give you 35 pawns of it for your services and a copy of the Limes Tower spell. Or we can do the other deal.
Korvin holds out his hand to Petronius.
"Agreed!" Petronius shakes Korvin's hand and smiles. "We will, of course, have to put that agreement on parchment, and agree on a delivery calendar before actual work begins, but that should be a formality."
((We can handwave the actual contract and casting of the rituals. As for the lab text, it will be delivered once all towers have been raised. Add it to the library but credit me and Petronius with it.))
Conjuring the Limes Tower (CrTe 20, He req.)
R: Touch, D: Mom, T:Ind, Ritual
Creates a square tower of stone and timber, similar to the Roman towers built along the Limes Germanicus. The tower stands 40 feet high and is 20 feet wide, with a stone foundation but no basement. The interior design is set, with ground floor designed as a common room, while the three upper floors are designed as comfortable living quarters. This spell is flexible enough so that the actual appearance of the tower can be changed to reflect surrounding buildings and style.
(Base 3, +1 Touch, +3 size, +1 elaborate design)
((You can also go ahead and deduct the vis from the covenant's stores. This would be 24 pawns for the big towers and 56 pawns for the small towers, plus 35 pawns of aligned vis for Petronius's fee.))
((Petronius will offer to provide you with up to 10 pawns of Terram vis in exchange for an equal number of Vim, Ignem, Aquam, Auram or Herbam, as well as up to 10 pawns of Creo for an equivalent number of vis from another Technique. This will leave you to obtain 60 pawns of Creo or Terram vis through other means to fuel the rituals.))
((JL - Korvin will trade 80 pawns of Mentem for Terram. Normal rates would be 40 pawns of terram. Not sure if Korvin can get a better deal.
Korvin will trade Petronius 10 pawns of herbam and 10 pawns of Rego for 10 pawns of Terram and 10 pawns of Creo))
Korvin can get a better deal, a one for one exchange. Korvin hasn't done a large trade of this scale, and it's done with a wink and a nod that this is done by/for Korvin, and not Mons Electi. Doing this often will definitely increase the exchange rate...
Then Korvin can trade less. He will trade 60 Mentem for 60 Terram. I've updated the inventory (lines 179 and 180). Korvin is done unless you want to charge any other amount to the sewer system.
I'll just have Marcus do it. I think he can invent the spell, and, it would be mastered, and he could just cast it on round chamber pots...
Let's say that the design of the buildings that Petronius makes has a WC, of sorts, with a spot that is round, and fixed, and is a defined ring. Then, Marcus can invent and cast a spell on each spot with circle target and ring duration... Does that sound reasonable?
Sounds good. Let me know the cost of Marcus' time.
Well, it's part of the Charter, IIRC, that a Guest must provide some service to the covenant on a periodic basis. We can call this his method of service.
Is there anything else that needs to happen here?
Apropos of nothing, but Fiona will ask Praxiteles and Alips if they know of any exceptionally talented musicians who might be willing to play at Tribunal in a couple of years. Don't have to be magi.
She also checks with Moire to see if she knows of any amongst the covenfolk.
They offer to secure a few musicians...